Based on my experiences racing with a set of Enve Twenty9 XC tubulars (25mm wide) and training rides on a set of Chinese XC carbon clinchers (19.5mm inner diamter), I agree that 19mm should be the minimum inner width.

Based on my experiences racing with a set of Enve Twenty9 XC tubulars (25mm wide) and training rides on a set of Chinese XC carbon clinchers (19.5mm inner diamter), I agree that 19mm should be the minimum inner width.

Most cyclocross racers use road rims. That means about 19-20mm outer width, and 13-14mm inner width. For example, a classic road rim, the Mavic Open Pro is 19.5mm outer and 13.8mm inner. Those are the rims I use on my 'cross bike. I have also used 'cross tires on Salsa Deldago Cross rims, which was fine. They are 22.5mm outer, and 18mm inner.

Take the Easton!
I ride my Crest tubeless with 700x32 tyres. Inner wide is 21 mm - with the new BST itīs like 22 mm on traditionel rims.The wider rim makes the tyre more stable by low pressure.

@ AKxc - ^^ what he said. According to Easton the Haven 29er rims have an internal width of 21mm - very common size for mtn rims. I've run mine on Alex DA rims and have had no problems. I would say the only thing to keep an eye open for is if you have enough clearance in the frame and fork.